Automatic peed-regulating mechanism



Feb. 9 1926. 1,571,940

P. J. GAGNON, JR

AUTOMATIC FEED REGULATING MECHANISM Filed April 10, 1924 2 Sheets-Sheet 1 Fig. 1.

lnve mdr. Peer J. Gagnon Jr.

7% Maw Affya.

has Feb. 9,1926. i 1.571946 UNITED STATES PATENT orrics.

PETER J. GAGNON, JR, E LOWELL, MASSACHUSETTS, ASSIGNOR 0E ONE-THIRD To JOSEPH L. HENDERSON AND ONE-THIRD To ALBERT J. GAGNON, BOTH 0E LowELL, MASSACHUSETTS. r a

'AUTOMATIC FEED-REGULATING MECHANISM.

,; 7 Application filer]. April 10, 1924. Serial No. 705,572.

To all whom a may concern; less than a predetermined variation in fluid Be it known that I, PETER J. GAeNoN, J12, pressure when the regulating means is a citizen of the United States, and a resident a-uton'iatically controlled by variations in of Lowell, county of Middlesex, State of pressure ina passage, the pressure in which lilassachusetts, have invented an Improvevaries in correlation to the amount of mament in Automatic Feed-Regulating Mechaterial delivered to, or from, or consumed by, nism, of which the following description in the machine, for example, in machines havconnection with the accompanying drawing, ing air separators, such as, grinding mais a specification, like characters on the chines to which the material to be ground 10 drawing representing like parts. is delivered by the feeding mechanism and This invention relates to improvements the ground material removed from the in regulating devices for intermittently grinding chamber by an air separator. operable feeding mechanisms and the object The present invention is adapted to conthereof is to provide a novel regulating trol the amount of material delivered to 6 means for controlling the actuation of the the grinding mill in correlation to the feeding mechanism. variation in fluid pressure in the separating More particularly the invention relates to chamber, thereby automatically preventing feeding mechanisms comprising an interthe delivery of too great an amount of mamittently rotatable member operated by a termite the grinding chamber which would 20 pawl and ratchet mechanism and one of the prevent proper operation of the grinding objects of the invention is to provide a novel mechanism and by such regulation mainand improved pawl mechanism in which the taming a uniform suction in the air sepapawl controlling means is directly mounted rator which will insure the delivery of a upon the pawl carrier. substantially uniform product. By pre- A further object of the invention is to venting the actuation of the regulating provide a novel pawl mechanism which can means uponless than a predetermined varibe readily substituted for the pawl of usual ation of fluid pressure in the air separator types of machines of this character. unnecessary stopping and starting of the A further object of the invention is to feeding mechanism is avoided without in- 30 provide a. pawl mechanism comprising a terfering with the proper and efficient operreversible pawl thereby adapting the device ation of the mill and wear and tear upon to rotate the ratchet either in a clockwise the regulating mechanism reduced to a minior counter-clockwise direction. mum.

These objects are accomplished in V the Thefeed regulating mechanism is adapt- 35 present invention by providing a pawl suped to various uses, such, for example, as port in which is mounted a preferably controlling the feeding mechanism of fuel reversible pawl which is controlled by an feeders for heating furnaces or steam boiler electro-magnet mounted directly upon the furnaces in which the feed regulator may be pawl support, the support preferably being controlled by variations in air or ,steam 40 of such a character that it can bereadily pressure in the passage leading to the fur-' mounted upon the usual pawl carrier of the nace, or by variations in the pressure within feeding mechanisms of this general type. the furnace itself, or in the flue leading from The action of the electromagnet may be the furnace, or the feed regulator may be controlled in any suitable manner as by an controlled by the variations in steam pres- 45 automatically operable switch mechanism sure in the boiler or in pipes leading thereactuated by mechanical means or by variafrom, or by variations of the speed of tions in fluid pressure, either above or be: motors actuated by the steam from the low atmospheric pressure, or by variations boiler. in voltage of an electric circuit, or otherwise. In short the present invention, in its broad 50 A further important object of the invensense, comprises means for automatically tion is to provide means for preventing the controlling the feed regulating mechanism actuation of the feed regulating means upon of the pawl and ratchet type upon var1at1ons ot' condition in the machine or its aeeesseries which are correlated to the amount of material delivered by the feeding mechanism, the operation of the controlling mechanism being; so governed as not to actuate the feeding mechanism upon less than a predetermined tariation oi the eon dition of the medium which controls the regulator.

. A preferred embodiment of the present invention illustrated herein as applied to the regulating mechanism disclosed in my prior Patent 'Ko. l...-t2l,,l-t3 grai'ited June 27, 1.922, tor automatic :teed regulator for machines: having air sepa atom. It will, how ever, be understood that: the invention de scribed herein is of general utility and is applicable to various other machines and mechanisms, within the svope ot the claims.

In the drawings:

Fig. l comprieea an elevation ot a centrifugal grinding; mill ol the llaynioiid type illust'ating the present invention applied thereto;

Fig. 52 it; a detail riew oi a portion of the bane of the mill showing}; the ports through which air admitted into the mill;

Fig. I, an enlarged detail View, partly in vertical section, 1 't' the novel pawl mechanism embodying the intention in operative relation to the ratchet oi the rot ar lceding member;

Fig. l in an enlarged detail side elevation of the mechanism illustrated in .l ig. El; and,

.l ia'. o is an enlarged detail elevation of a portion oi' the regulating;- mechanism.

The machine illustrated in the aeompartying drawings a centrifugal grinding mill ot' the well. known laymoi'nl type having an air v cparat'i'ir and a collector for the linished material. .l o'inn of this general type of grinding mill are illuat'ated and described in Patent No St lton gr: ntcd to A. Raymond h eptrmber t. i908.

As illustrated in the drawingra the mill is Supported upon a suitable bed 1, and coinprises: t trame 3 having a grimlinp; ring 3 whicn eo-operate gal. rollers t so a with a eer'ea ot centrifupportcd upon shafts (not shown) which a 'e pivotally eccured at their upper ends to a spider -ar *ied by a rerti a eha't'thaving" at its lower end a near which is driven by a bevel gear 5 upon a main driving shaft (3. The grinding ring and co-o icratiug centritut al rollers are lUfdtGtl a short dietznice above the bottom of the Q'Lllltlli'lg chamber and the material which in tied into the mill drops into the grinding chamber and is thrown upwardly into the path ot the rollere by plows which are carried by a sleeve aha-[t connected to the spider which act: rates the ccntrit unal rollerr as dim {nosed in the prior patent atorcsaid.

The material is led into the grinding:

top 8 ol the air aegmr:

chamber by a pocketed rotatable cylinder which is intermittently actuated by pawl and ratchet mechanism.

The air separating chamber in this type 0t mill lo -ated above and torn'is a eon tinnation ot the grinding chamber. The wall 7 ot the air aeparating; chamber extends upwardly from the grinding ring and expandn slightly outwrnatty. thereby being (it inverted truncated coniczl form. The tor is of conical :toen'i and communicattw with a central in wardl extending pipe S) which leada to the eye o't-a blower ll) which diachargrea througl a pipe ll tangentially into the cylindrieal upper portion 12 ot' a dual collector oil the cyclone type hitting, a dinruwardly extending; conical barrel i p oridcd at in: bottom with a hopper til'rom which the liniahed material may be discharged. it pipe to leads .troin the center ot the top ol" the cylindri :al portion of the collector to a drum it) which ciittlofOF; the lower portion of the grinding chamber which cxl'enda below the grinding ring. it aerica ot tangential iort,--: torn'ied by vertical walla l7, lead lroni the drum 1(5 to the grunting; chamber beneath the grind lll ll' ring.

The air separating chamber which is enclosed bylhc wall I and top ti and the pipe 3) leading; thcre'l'rom to the blower form a conduit through which the air laden with finely ground material is drawn trom the grinding: chamber.

lvl aterial is ted into the ggrhalingr chamber through a chute or hopper ltl which leads to a pocketed rotatable cylii'idcr which mounted upon a nhat't it) which in rotated by a ratchct :lt 'lhe material delive-red by the rotatable pocketed roll drops to the bottom ot' the (Ztiiitllllg chamber. A series-i oi ports. formed by vertical converging walla, lead 'troin the drum it; to the lower portion of the grinding ehaiubcr beneath the grinding ring. 'llun the current ot air produced by the blower drawn the llnely around ma- 'hainber terial from the air acpaiutnu t and delivers it to the collector to which the material is depot; livercd trom ll led and the air is then clee collector into the druinltl from which it enters the mill through the tangential ports:v below the grinding; ehamber.

it, during); the operation of the milh an excessive amount of material is led into the grinding chamber. the tangential admission ports for the air become more or leno tilled up and clongjged thereby shutting oil' the tree ent-amrc of air into the mill and conse qncntlydiminiehingr the air pressure within the air Stlilll'ut'fll'. 'lhin aeriouaiy modifies the action of the separator and alat interlerra with the proper l'uncticming ol? the mill.

urinal types ot' the llaymond mills set forthin Patent No. 897,400 above described means were provided for manually regulating the feeding mechanism for the purpose of correlating the amount of material fed to that which was properly ground which was attached to ,a reciprocating pawl which engaged the ratchet of the feed roller and which when energized would remove the pawl from engagement with the ratchet of the feed roller.

Bythe present invention the controlling me eha ism disclosed in my prior patent. aforesaid is simplified and further improved by the provision of means for preventing actuation of the regulating device unless a predetermined variation in fluid pressure in the air separator is attained. The pawl mechanism is so designed that it may be readily substituted for the usual types of pawl mechanisms employed in mills of this character and also for similar pawl mechanisms of other machines.

The invention in its broader aspect comprises improvements in feed regulating devices and other intermittently operated pawl-actuated mechanisms in which it is desirable to correlate the intermittently actuated device to the demand of the machine or apparatus to or from which the material is delivered or in which it isconsumed or otherwise treated by controlling the operation of the feeding mechanism from variations of pressure in a chamber or other conduit, the fluid pressure in which is dependent upon the demand or proper operation of the machine.

The terms fluid pressure and air pressure are used herein in a broad sense as including pressures either above atmospheric pressure or pressures below atmospheric pressure such as are produced by suction.

In the illustrative embodiment of the invention shown in the drawings, in which the feeding mechanism delivers material to a grinding chamber of a grinding mill, the mechanism for actuating the feeding-ratchet 20, which is connected to the shaft of the feed roll, comprises a pawl carrier having arms 22 and 23 located upon opposite sides of the ratchet and pivotally movable about the axis of the shaft 19, the arms 22 and 23 being connected by webs 24 and 25 thereby producing a rigid pawl-carrying frame structure. A shaft 26, also connecting the arms 22 and 23, provides a pivotal support for the pawl, in the usual.constructions, which engages the ratchet 20. The arm 23 extends a considerable distance above the periphery of the ratchet and is provided with a stud shaft 27 which is connected by a link 28 to a crank 29 upon a shaft 30 which is driven in any suitable manner from the actuating mechanism of the machine, as, for example, through a belt pulley 31.

In the construction disclosed in my prior Patent No. 1,421,343 the usual pawl for rotating the ratchet of thepocketed feeding roller is shown as connected by a link to a suitably supported solenoid the circuit of which is controlled by a pneumatically actuated switch mechanism which is operated by variations of pressure in the air separator.

In the present invention the solenoid is mounted directly upon the pawl carrier and in the preferred construction illustrated herein a pawl support is provided which can be readily mounted upon the pawl. carrier above described which is employed in the usual Raymon I type of machine.

The pawl support shown in the accompanying drawings comprises a plate or bar 32 having an aperture 33 to receive the shaft 26 upon which the usual pawl is mounted and is provided at its opposite end with a bifurcated offset extension 34 which embraces the web 24 of the pawl carrier. Thus the pawl support 32 may be readily assembled upon the usual pawl carrier by merely withdrawing the shaft 26, removing the original pawl, then applying the bifurcated end of the pawl support upon the web 24 and reinserting the shaft 26. The pawl support 32 is provided with a vertical slot 35 in which a pawl 36 is slidably mounted and is caused to rest, by the action of gravity, upon the teeth of the ratchet 20. of the pawl 36 is rigidly connected by a bar 37 of brass, or other nonconductor of magnetic lines of force, to the lower end of the core 38 of a solenoid 39 carried by a frame 40 having standards 41 provided with slotted laterally extending feet 42 which are secured by machine screws or bolts 43 to the upper face of the pawl support 32. The slot 35 in the pawl support desirably is of rectangular cross section and the pawl 36 of corresponding rectangular cross section so that the pawl 36 maybe reversed in case the teeth of the ratchet 20 are reversely arranged. Thus the pawl carrier may be readily adapted to any feeding mechanism of the ratchet and pawl type.

The current supplied to the solenoid 39 may be controlled in any suitable manner, either manually or automatically, within the scope of the claims which are addressed to the ratchet-actuating mechanism. In the present embodiment of the invention the solenoid control is effected through a pneumatically actuated device, connected to the air separator, similar to that disclosed in my prior patent aforesaid.

The upper end The controlling device illustrated conn prises a conical pneumatic chamber a l which is mounted in the ipper end ol a suitable box or receptacle :lzt which may be secured to the wall of the room or to the mill in any convenient position. The upper end of the pneumatic chamber in connected to the air separator by a conduit lb, prefe"- ably having a flexible section ii such as, a piece oi rubber hose, to prcrent transmission of the vibration of the mill to the pneumatic chamber. The lower end ol? the pneumatic chamber llis closed by a flexible dia phrae'm lit to which is secured a rertica switch rod ll) having a later: ll extending contact plate 51), the lower end of the rod l-S) la ing slidably moun'cd in a braclcet oi mounted upon a suitable insulating plate on secured to the wall oi the regulator box or receptzn-le in. it helical spring as, connected at one end to the bar l!) and at the other end to a boss i-lupon the bracket 51, tends to hold the ioritch rod l-il against its b aring in the end of the brachet iii and thereby prevent vibration of this dependinsl rod. M

'lhe current from a suitable generator which tor convenience oi illustration shown as a battery 5?), leads to a lmite switch at, one of the terminals 5? ol which in connected l y a -onductor an to the contact rod it). 'lhc other terminal to oi the switch is connected to a conductor tit) which leads to the solenoid 3t and the return conductor (ll from the solenoid leads to a binding post 6:! upon an L-shaped spring arm (33 which extends over the contact plate so and is pro rided with an adjustable contact member or screw til; located lllllllttllltltily above a ((llHlJltdlttlltill' contact member on the plate ht).

hen in the operation oi? the machine the air pressure in tl e air separator is diinin- 'ishcd by the clogging up Oil: the air admission ports in the lower portion oi the grinding chamber the diaphragm :lii oi? the pneumatic chamber -ll-l will be raised thereby causing: the contact plate St) to engage the conipleinentary contact member li t at the end oi the spring arm tit; thereby completing' the circuit from the sritch through the conductor 55-h the contact members it) and til, the apring arm 33 to the solenoid and thence throngjgh the conductor to to the other terminal it oi the switch fit}. The solenoid. when energized by the current, will withdraw and withhold the pawl 'l roui engage ment with the 'atchet until the material in the base oi the grinding chamber has been sulliciently reduced to admit enough air to increase the air pressi'ire in the separator to a point at which the diaphragm in the pneumatic chamber will be permitted to descend sullicientl i' to break the contact between the plate 50 and the complementary contact /lL plate St) upon the rod ill to engage the coin-' member (i l-V. When the circuit is thus broken the pawl will drop by the action of g 'avity into engagement with the teeth oi the ratchet 2t) and feeding oi the l'naterial will be resumed.

It has been found by experience that this control may in some instances be too sensitire and will cause unnecessarily frequent actuations of the lieediug mechanism. Anotherobject ot the invention is to provide means for reducing the sonsitireness ol? the control. This is accomplished by providing means which will prevent the SPPtLI'ttllOll ot the contactmembers tit) and (let upon less than a predetermined variation of the air pressure in the sepa ating chambers, or in other words, until th: amount of suction in the air chamber has been reduced to a pre detefmined amount. 'l.hi:-s is accomplished by providing automatically operable means for 'l'lexing the spring ('33 which carries the contact member (34 in a directionto maintain the contact members in contact until a pre determined condition o'l air presenn'e in the separating chamber has been established.

ln the illustrative embodiment of the in- \ention disclosed herein a supplementary solenoid 5 is mounted ina suitable linacket no upon one ol? the. walls of the box l5 and the core of of the solenoid provided with an aperture havingan insulated lining (38 into which projects a .spriiig 9 which is coiled intermediate ot its ends upon a boss To -arried bya bracket Tl which is eecured to another wall oi? the box 45. The opposite.

endii oi? the spring extends acrosss and normally lighttt engages the spring' contact member 3 at asullicientd'stance from its support to enable it lOWlQPTQFS the spring contact member (33 when the solenoid (35 is energized. 'lhe solenoidtili is located in a shunt "from the conductors leading to the pawl-actuating solenoid 39. JiH illustrated herein?the"ronductor (it) is connected to a binding, post i'il mounted in the box if) and a shunt (.(Jlltitltttll' Tl runa from this binding post to the solenoid 35. A conductor '75 runsdrom the solenoid (58 to the binding post (52 upon-the spring; contact memberoll. Consequently when the llll diaph 'ag'ni is raised bydiminution of air no sulliciently to cause the contact plementary contact member (it upon the spring contactmemla-r (33 a current will not only be passed through the pawl-actuallug s-olenoid ll, but also through thesupplenientary solenoid 35. The core (37 ot the solenoid will then be 'aised. causing; the spring;- ttll to be pi\ 'otall moved about its fulcrum TtL thereby causing; its end to press down upon the spring);contact member o l. thereby 'i'orch'ic" thecontact member (34:

more firmly into engagcu'ient with the con tact plate 50 and maintaining it in Such po- .77, may be provided to adjust the limits of movement of the solenoid core 67, thereby providing an accurate control of the action of the supplemental solenoid and consequently controlling the effective movements of the contact members and 64. By adjusting the position of the adjustable contact member 64 the amount of variation of air pressure in the pneumatic chamber 44 required to make and break the circuits leading to the solenoid may be accurately determined and the actuationof the contact members upon variations of air pressure in the air chamber less than a predetermined amount prevented.

It will be understood that the embodiment of the invention disclosed herein is of an illustrative character and is not restrictive and that various changes in form, construction and arrangementof parts may be made within the spirit and scope of the following claims.

It will also be understood that the. in vention is adapted to other uses than upon feeding mechanisms to which reference has been made, for example, a screw conveyer leading to av weighing machine and intermittently rotatedby pawl and ratchet mechanism may be equipped with the present invention and the actuation of the conveyer arrested by a switch in the electric circuit of the solenoid operable by the scale beam when a predetermined amount of material has been delivered to the scale; the actuation of the feeding mechanism for any motor driven machine may be controlled by a switch actuated when a predetermined variation of voltage is attained. The invention also may be applied'to any machine or apparatus having a conduit chamber or other passage which is subject to variation in fluid pressure dependent upon, or correlated to, the amount ofmaterial delivered to or from or consumed within the apparatus or a part of it as willbe obvious to those skilled in the art to which such machine or apparatus relates.

Having thus describedthe IDVQHtlOlLJVllM) by LettersPatent, is: V I

1. In a machine comprising arotatable member and meansfor actuating the same including a ratchetand a co-operating pawl, a r eciprocable pawlcarrier, an electromagis claimed as new, and desired to be secured net mounted on said pawl carrier for controlling the relation of said pawl to said ratchet, means for supplying an electric current to said electromagnet and means for controlling said current whereby said pawl may be caused to engage, or to be disengaged from, said ratchet.

. 2. In a machine comprising a rotatable member and means for actuating the same including a ratchet and a co-operating pawl, a reciprocable pawl carrier, an electromagnet mounted on said pawl carrier, a pawl slidably mounted in said pawl carrier normally engaging said ratchet, but movable out of engagement by said electromagnet when the latter is energized, means for supplying an electric current to said electromagnet and means for controlling said current. i I

3. In a machine comprising a rotatable member and means for actuating the same including a ratchet and a co-operating pawl, a reciprocable pawl carrier, an electromagnetmounted on said pawl carrier, a reversible pawl slidablymounted in said pawl carrier normally engaging said ratchet operable alternatively to engage ratchets provided with reversely arranged teeth, means for supplying an electric current to said magnet to cause the same when energized to remove said pawl from engagement with said ratchet and means for controlling said current.

4'. In a machine comprising a rotatable member and means for actuating the same including a ratchet, a co-operatingpawl,' a. solenoid having a core, a non-conductor of magnetic, lines of forces connecting said core to said pawl, a reciprocable carrier supporting said solenoid, means for supplying an electric current to said solenoid and means for controlling said current to cause said solenoid when energized to remove said pawl from engagement with said ratchet.

5. In a machine comprising a rotatable member, means for actuating the same in.- termittently including a ratchet, a reciprocable pawl carrier, a solenoid having a support detachably mounted on said pawl carrier, a pawl slidably mounted in said support and normally engaging said ratchet, a non-conductor of magnetic lines of forces connecting said pawl rigidly to the core of said solenoid, means for supplying an electric current to said solenoid and means for controlling said current to cause said solenoid when energized to, remove said pawl from engagement with said. ratchetl 6,;In a machine comprisinga rotatable member and means for actuating the same intermittently including a ratchet, a pawl carrier having arms located on opposite sides of said ratchet, pivotally movable about the axis of said ratchet and having e e s conne ting, said arms, an electra iii .magneti having a support adapted lo he secured to said armeonnecting members, a pawl slidahly mounted in said support normally engaging: said ratchet, 111011111: l or supl ri11;,: an electric current to said electromae'uelx 10 cause the same when energized lo rennore said pawl 'lroni said ratchet and means for conl'rollingr said clecl'ric current.

i. All pawl mechanism for 11111ch1nes haring; an inter nillentl aclnated roiatahle meinher prorided with 11 ratchet comprising a pawl rarrier having arms located upon opposilesldcs 0'1 said ratchet and pivolally movable about the axis 01" said ralchel' and (JUllllCCliCll by a web and by a shall; spaced apart ll'fllll said weh, a pawl support having means respectively 10 engage said weh and said sha'llf, a pawl slidahly mounted in said support adapted normally lo engage said 'al'chet and an eleclroniaggnet niounfed upon said pawl supportand operahle when enernixed l'o remove said pawl from engagement wil'h said ralchet.

51. A pawl mechanism for machines having;' an inliermilteniily actuated rolialahle memher provided with a ratchet comprising a pawl carrier having arms located upon opposil'e sides 01 eahlralchel: and pirolall movable ahout lhe axis 0'! said ratchet and eonnecled l1 a weh and hr 11 shall spaced aparlr l'roin said weh. a pawl support liar ing means respra'lirelr lo OHLKIZIQIQ said \\'1,l,)

and said shall. a pawl slidahlrnainnled in saidaupporl' adapled norn'iallr to engrave said ralchet a solenoid mounled on aanl aupp'orl having 11 c0re rigidly connecled in said pawl hr 11 11on-co11duei;or ol niagi'nii li wherein: raid 1:: nnohl rrhen lines oil lorc energized will remove said pawl from e11- inenl with aaid rareher. ll. In 11 111111 1111111 ol i'he ulnar; descrihed har 111;: an inlerlnill'enlly operah rotalahle feeding mechanism for auprdyiii r maierial lherelo and 11 1111111 11111 suhjeel to \arialioria in l'lnid p easure in reeponae lo the demands of the maehinin r'ernilal'ineg means illll'mlllllinilly operahle rr (he rarialions of fluid pressure from a dcl'inil e pressure in said pa.

sage lo conlrol said feeding: 1110111111 and means lor pri'wenlzinu actuation of said regulating means upon variations of pressure less than :1 predel'ermined 11111011111 from said delinile pressure.

Ill. ,ln :1 machine of lhe clasa deucrlhed l11'1ri11 1- an iniiu'milleully operuhle lending 1ueelani1- 1n l'or aupplying' malarial lherelo, means including an eleclromagnet for controlling Said feeding 11111111151, a conduit sub- 1 ject to variations in fluid pressurein response to lhe demands of the machine a Pl'lGUlIml'lG chamhca' eonnnunieal'i11 wil'h said conduit,

a switch in the cireuic ol said eleclron:agnet operahle hr variations in pressure in said plieinnaiio chamber from a delinil'e prrassnre and 1111 111111 lor ucrenlinpj l'he actuation of said switeh upon variations ol pressure loss than a predetermined amount from 51nd delinil'e pressure.

11. In a machine. of the class deserihd haringl an inlerinitlenlly operable Feeding; mechanism for sup]1l' ing material thereto, 111011111; including an elecl'roniagnel' for conlrolling said 'leedimg'inanai, :1L()1l(llllll5lll)l(fil in variations in lluid pre1==aure in response to the demands of the machine, a pneumatic chamher connnnui 11111;; with said conduit a switch in the circuit of said electromagnel: ope'ahl1 1 by variations in 1.1ressure in said ineuinatic chamber ;l"r01n a definite pressure, a shunt from the circuit of said electr01nagnel, a supplementary eleetroinagnet in said shunt circuit and mrans operable by said supplementary magnet to prevent;actuation of said switch upon variations of pressure loss than a predetermined amount ifl'Olll said definite pressure.

12. 1'11 11 machine o'l l'he class descrihed having an interinill'enl'ly operzhle :leeding uaurhanism for supplying material, thereto, means including an eleeliromagnet :lor conl'rolling said il eeding means, a conduit subject to rarialions in air pressure in response 10 the demands o'l ihemaehine a pneumatic ehamher eonnnnnicalingr wilh said conduit, a switch in l'he circuil' ol said electron111111101, oper: l1le l1\"211l{llll ]llfr1 in 1111 131111110 in said pneumal-ie chaniher from a delinile pressure, a shunt from lho eircuiluojl said ieleel romagn net. :1 snpplemcnlarr elecl'romagrnel in said shunl circuil. resilient means operahlo 1 1' said sumdemenlarr magnet engaging; eaid arrilch 110i inp; lo prerenl (he operalion l'here ol' hy ariationa of pressure less than a pre riletern'iinecl ainonnl from said definite pres-- sure. 1 1 1. in a inaiiihinenil the class dcscrihed ceinpriuinpg jinclin e; 111 1111511 rolalahlc l'eedh1g1 means including a ratehel and a reciprocaling; pawl l'orrol'alingr lhe same and an air separalor l'or remorine 1he finished 111alcriah eleclrieally actualed 1110111111 iuclnrilinp; an l@(.'ll()]ll2l llll3 aida ided when energized lo render the, ael'ion ollsaid pawl iiielleclive, a swiloh in (he circull 0| said electroniagnel, means operable h a diminul'ion ol the air pressure in said air sernn'al'or below a delinile pressure to cause said switch lo complelo the circuili of said eleelroumgnel and means for preventing inlerruplion ol" liho eolnploled circuit until said delinile pleasure in saidair aeparrlor has heen. established.

ll. In a machine olit lieelass described comprisinggrinding means, means for feed 10:1 llmparlial 1 11111111111 iirsaidaeparaling chamber from a definite pressure and means for preventing actuation of said regulating means by Variations in air pressure in said separating chamber less than a predetermined amount from said definite pressure.

15. In a. machine of the class described comprising feeding means, a separating chamber and means for creating a suction of air through said separating chamber to remove the finely ground material therefrom, regulating means for arresting the feeding of the material to the machine operable by the diminution of the air pressure in said air chamber below a definite pressure and means for preventing the actuation of said regulating means upon less than a predetermined amount of diminution of air pressure below said definite pressure.

In testimony whereof, I have signed my name to this specification.

PETER J. GAGNON, JR. 

